Locomotive-valve gear



Jann l N. VANDRHORST Locorac/)TIVE VALVE GEAR Filed March 11, 1927 2 Sheets-Sheet 1 77. l/anoferkovSlL I LOCOMOTIVE VALVE GEAR Filed March 11, 1927 2 Sheets-Sheet Patented `Fan.. l, 1929.

STATES PATENT OFFICE.

NICHOLAS vnamnnnons'r, OF LONDON, ENGLAND, AssIGNOR 'ro HERMAN LINnARs,

, or LONDON, ENGLAND.

LOCOMOTIVE-VALVE GEAR.

Application filed. March 11, 19%?. Serial No. 174,571.

This invention relates to counterflow locomotive steam engines of the type employing steam distribution 'valves other than the usual piston or slide valves, more particu larly to the valve gear of such engines.

ln modern locomotive practice the tendency is to use steam both of high pressure and high degree of superheat, and considerable diiiiculties have been met when, for

lo example, the ordinary long travel slide or piston valve is used.under such conditions. To obviate the comparatively, long travel and large wearing surfaces needed by slide or piston valves controlling, for example,

ia live and exhaust steam ports for both ends being of complicated or irregular design` of the cylinder and requiring considerable lubrication, ithas been proposed to use short travel poppet or like valves each pair of same controlling the steam events- 2o on one side of the piston` Such valves, however, havekrlike the long travel valves,

been used in a casing or plurality of cash ings cast integrally with the cylinder body thus necessitating the said cylinder Acasting and very difiicult to cast, lparticularly as such cylinders for working with high pressure and superheated steam have to be made of cast steel.

The intricate cylinder casting as above is at all times in direct contact at one or more regions with the live steam and the risks of breakages due to the unavoidable and uneven expansion are very great.

The clearance volumes -should be kept to a minimum for efficient working and the passageways traversed by the steam, should be short and as far as possible free from abrupt corners.

Space being a serious consideration in gear, using short travel valves and a cylinder of simplified and cheapened construction on which are cast only such parts as are necessary to secure it to the locomotive frame and, if required, to carry the valve actuating mechanism.

In carrying my invention into effect, the valves are arranged in housings cast integrally with the detachable cylinder end covers, and are further preferably all larranged 1n such a way as to allow of their being actuated from above, and of easy accessin bility for inspection and cleaning pnrpcscs, which are so essential in locomotive practice where space is a serious consideration.

In order that my invention may be understood drawings are appended, in which Figure l is a fragmentary vertical longitudinal section in a plane parallel withthe cylinder axis and including the centre line of the steam inlet valve at one end;

Figure 2 is a similar view to Figure l on a plane including the centre line of the exhaust valve;

Figure 3 is a vertical section on a plane including the centre lines of both valves, that is, normal to the cylinder axis;

Figure 4 shows an outside view in perspective of the cylinder casting with the end covers removed showing the simple construction thereof permitted by the present invention.

Referring,`now, to Figure 3, the valves a, b are arranged inl housings in a casting c of the shape shown which is formed integrally with the cylinder end cover fiange d. .A similar casting and valve arrangement is provided at the other end of the cylinder, but reversed left for right, one only being hereinafter described, the description applying equally to both. The valves are disposed symmetrically one on each side of a vertical plane including the centre line of the cylinder as shown and are provided with seatings e, el formed by the openings fx f1 in the horizontal partitions in the housings. The valve heads are car- 1 ried on spindles g, g1, which can be axially moved within guides li, h, respectively.

These guides may be of brass, gun metal or other material and are arranged with their centres parallel to one another and at right angles to the cylinder axis, bein a firm and preferably slightly tapered lit rom the interior of the valve housing through the extensions-Or bosses z', l above thelatter.

sides of the respective housings.

The upper end of each valve spindl'ehc'arries a sprmg cap which retains in positlon a compression spring k surrounding the spindle and bearing at its lower end against t e top of the boss z'. As shown in Figure l, live steam is admitted by the pipe Z into the outer passage m below the valve a. On exerting downward pressure on the spindle g against resistance of the spring 7c the valve a is lowered from its seatings and steam is allowed to pass through the opening f and by way-of the passage n into the cylinder o, where it acts upon the piston p.

4The exhaust valve operates in a similar manner. As shown in Figure 2 exhaust steam from the cylinder space passes into the space m1 below and on the inner side of the valve b and, when the latter is opened against the spring 1:1, the steam passes through the opening f1 into the space nl. The steam is then conducted away by means of the elbow pipes or bends g, g1, as shown in Figures 3 and 4,.to the funnel, for example through the passage g2, q2 in the bracket e of.

the cylinder.

The valves may be actuated by any means preferably such as will not necessitate the various steam and exhaust events for either or both ends being mutually dependent. The separate cam arrangement for each valve as shown in Figure 1, is, however, preferred. The cam r is carried upon the shaft r1 situated transversely of the cylinder and rotatably mounted conveniently on the brackets 'r2 secured to the top of the pad w cast on the cylinder top. Rotation of the cam causes the push vrod s to reciprocate in its guides t, t1, a roller s, being preferably provided for reducing friction. At its other end the push rod thrusts against one arm of a bell-crank lever u which is swivelably carried on a horizontal transverse pivot u, secured to or cast integrally with the flange al. The other arm of the bell-crank u is provided with adjusting means, such as a screw, fv, the lower end of which bears upon the upper end w of the valve spindle. The shape of the cam can be such that in rotating at a uniform angular velocity it actuates the valve as desired through the intermediary of the gear above described. The screw o allows of adjustment and the taking up of wear and tear.

In all cases the valves are situated as close as possible to the cylinder and sharp bends and other such obstructions to the even flow of steam are avoided, which makes the invention particularly suitable for use in, for example, high s eed or passenger locomotives, and it w' be seen the parts of the cylinder cover and valve housings whichare subjected to high pressure and high temperature are of a 'simple design and thus constitute an improvement in that the invention overcomes.the disadvantages hereinbefore indicated.

.In addition it will be seen that the live and exhaust steam cavities fm, m1 respectively are so arranged as to reduce as far as possible thc clearance volumes behind the piston.

Accessibility to the valves and housings is provided for by the circula-r openings y, y1' concentric with and below the valves. These openings are such as. to allow the valves to pass through. The only work necessary is to remove the fianges which normally cover said openings and, after detaching the spring caps, j, j from the respective valve spindles, pull the valves out together with their spindles. The guides k, it, as distinct from known practice are adapted to be undisturbed by the above procedure and to remain in position, being tightly fitted in the upper parts of the housings. The design, however, also permits of withdrawing said guides readily if desired. The valve actuating mechanisms it is to be noted, in the arrangement shown in the drawings, likewise do not require to be disturbed, and being all arranged above the cylinder or valve housings are themselves easily accessible for adjustment or the like. f

It is to be understood that modifications and additions ma be made to the foregoing construction wit out departing from the spirit of the invention a's set out in my appended claims.

Having now described my invention, what I claim as new and desire to serure by Letters Patent is zl,

1. In a double acting counterlow locomotive steam engine havinga pair of poppet valves for each end, the combination with a substantially plain' non-ported steam cylinder and means for securing same in a substantially horizontal position to the locomotive frame, 'of separate end covers for said cylinder each of said covers having cast thereon in close communication with the respective end of said cylinder, housings for one pair of said valves adapted to carry said' pair of valves in an inverted position substantially symmetrically one on each side of a vertical plane containing the cylinder axis with their axes of displacement substantially normal to a horizontal axial plane, and said valves each being operatable from one and. the sameside of said lastmentioned. plane and accessible and removable from the other side of the latter.

2. The combination accordin to claim 1l having a balanced poppet v ve vin each housing, an upwardly extending spindle connected to each valve, guiding means for each spindle in the respective housing and extend-I llo y of said housings,

' each of said pair seatings, and mechanical above said valves for displacin ing upwardly through the top thereof, a pair of inverted seatings in each housing for each valve, resilient means externally of said housings adapted to hold said valves upwardly against`their respective seatings, mechanical means externally of and above said cylinder for i dependently actuating said valves and adapted to open same by downward thrust upon the spindles thereof, and means for withdrawing said valves from said housings from below without disturbing the said seatings spindle guides and actuating mechanism.

3. yThe combination claimed in claim 1 having a pair of isolated valve housings cast side by side on the outer face of each of said covers, a vertically operative balanced two face valve and horizontallyqsuperposed double seatings therefor in each housing, spindles attached lto said valves and extending upwardly through apertures in the tops guides for said valve spindles each providing the upper seating for the respective valve and extending upwardly with said spindles, steam 'passages in said housings, ports in each cover vconnecting the interior of the cylinder with of housings respectively above and below the valves therein, resilient means externally ofthe housings ing axially upon the valve spindles and holding lthe valves upwardly against said means disposed the latter froml said seatings against said resilient means. v

4. The combination claimed in claim 1 having' a pair of isolated valve housings `cast side by side on the exterior of each of said covers on opposite sides of the cylin-v der axis,

a horizontal partition in each v housing, an inverted balanced po pet valve in said housing vertically mova le within ya circular opening in .said partition, the under side of which is adapted to form the lower one .of two superposed seatings, a

V spindle coaxially connected to and extending -abovesaid valve and througillilthe top of said housing, a guide surroun the latter actvthe respective g said spindle passing firmly through anv aperture in the upper side of said housing and having a flange at its lower end within said housing,

carried on said covers for moving each ofsaid valves and opening them from above against the action of said spring means, and openings in the bottom `of each housing for removing said valves and valve -spindles independently of the guides and withoutl disturbing said cam means. l l

\ 5. In a locomotive having a horizontally disposed steam cylinder and a pairl of poppet valves for .each end thereof, the combination 'with a substantially plain nonpor-ted cylinder, of a detachablecover for -each .end thereof, said 'cover having two ports from its cylinder-engaging face respectively to the insides of two isolated valve housings cast side by side on a hori zontal diameter integrally 'onv its external face, an inverted balanced poppet valve and.

seatings therefor in each lhousing and closely adjacent to said external face, a spindle connected to, each valve and extending therefrom through guiding means penetrating housing, external resilient means adapted to lhold said valves against said seatings, and independently actuated transmission means for each valve externalnected to the respective valve spindles.

encircling the valve spindle exysaid flange forming the upper one of said v for admitting livey steam -ly of said housingsV and operatively con- In testimony whereof I have signed my b5 :name to this specification.

- N icHoLAs vANDERHoRsT. A 

